RAFLY 
OF  THE 

UNIVERSITY 
Of    ILLINOIS 


AGRICULTURE 


NON  CIRCULATING 

CHECK  FOR  UNBOUND 
CIRCULATING  COPY 


UNIVERSITY  OF  ILLINOIS 

Agricultural  Experiment  Station 


BULLETIN  No.  311 


NATIVE  CRABS:  THEIR  BEHAVIOR 
IN  BREEDING 

By  CHARLES  S.  CRANDALL 


URBANA,  ILLINOIS,  JUNE,  1928 


CONTENTS 

PAGE 

1.  Mains  coronaria   (L.)    Mill 536 

Malus  coronaria  as  the  Female  Parent 537 

Malus  coronaria  as  the  Male  Parent 538 

2.  Malus  angustifolia  (Ait.)  Michx 538 

Malus  angustifolia  as  the  Male  Parent 540 

3.  Malus  ioensis  (Wood)  Britton 542 

Malus  ioensis  as  the  Female  Parent 542 

4.  Malus  soulardi   (Bailey)   Britton 547 

Malus  soulardi  as  the  Female  Parent 548 

The  Mercer  County  Crab 550 

5.  Malus  jusca  (Rafin.)   Schneider 552 

Malus  jusca  as  the  Female  Parent 553 

6.  Malus  dawsoniana  Rehder 554 

7.  Self-Pollinations  of  Ap'ple  Forms 555 


NATIVE  CRABS:  THEIR  BEHAVIOR 
IN  BREEDING 

By  CHARLES  S.  CRAXDALL,  Chief  in  Plant  Breeding  in  Horticulture1 

Our  native  wild  crabs  have  received  frequent  mention  in  horticul- 
tural journals  and  reports,  and  the  suggestion  that  an  improved  race 
of  apple  varieties  should  be  bred  up  from  these  crabs  has  been  made 
by  various  writers.  There  are  some  records  of  experiments  in  hybrid- 
izing, but  these  are  meager,  do  not  go  into  details,  and  record  nothing 
beyond  pollination  of  flowers.  No  record  of  sustained  effort  in  the 
direction  of  breeding  the  native  crabs  or  of  attempts  to  breed  them  on 
any  extensive  scale  has  been  found  by  the  writer.  No  apple  variety 
known  to  have  a  native  wild  crab  as  a  near  ancestor  has  been  intro- 
duced, and  from  the  long  period  since  the  earliest  suggestion  of  breed- 
ing the  native  crabs  was  made,  it  is  a  fair  inference  that  the  suggestion 
has  not  been  acted  upon  and  that  such  efforts  as  have  been  made  met 
with  failure. 

Six  species  of  native  crabs  are  now  recognized.  Two  of  these  are 
Pacific  Coast  species,  one  is  northeastern,  one  southern,  and  two  belong 
to  the  Middle  West.  The  six  species  are  as  follows: 

1.  Mains  coronaria  (L)  Mill. 

Mains  coronaria  (L)  Mill.    Britton  and  Brown.    Illus.   Fl.  2,  235.    1897. 
Mains  coronaria  (L)  Miller's  Dictionary,  ed.  8,  no.  2.    1768. 
Pyrus  coronaria  Linnaeus  Spec.,  ed.  1,  480.    1753. 

2.  Mains  angustifolia   (Ait.)   Michx. 

Mains  angustifolia  (Ait.)  Michx.  Britton  and  Brown.   Illus.  Fl.  2,234.   1897. 
Mains  angustijolia  (Ait.)  Michx.    Fl.  Bor.  Amer.  1,  292.    1803. 
Pyrus  angustifolia  Ait.    Hort.  Kew.  ed.  1,  2,  176.     1789. 

3.  Mains  ioensis  (Wood)  Britton 

Mains  ioensis  (Wood)  Britton.  Britton  and  Brown.   Illus.  Fl.  2,  235.    1897. 
Pyrus  ioensis  Bailey.    Amer.  Card.  12,  473.     1891. 
Pyrus  coronaria  var.  ioensis  Wood,  Classbook,  333.     1860. 
Western  Crab  Apple 

4.  Mains  soulardi  (Bailey)  Britton 

Mains  soulardi  (Bailey)  Britton.  Britton  and  Brown.  Illus.  Fl.  2, 235.  1897. 
Pyrus  soulardi  Bailey.  Amer.  Card.  12,  473.  1891. 

Pyrus  ioensis  X  Pyrus  mains  Bailey,  L.  H.     Evolution  of  Our  Native 
Fruits,  189.     1898. 

5.  Mains  jusca  (Rafin.)  Schneider 

Mains  jusca  (Rafin.)  Schneider,  C.  K.  Illus.  Handb.  Laubholzh.  1,  723.  1906. 

Mains  rivularis  Roemer  Syn.  Mon.  3,  215.     1847. 

Pyrus  jusca  Rafinesque.    Med.  Fl.  2,  254.     1830. 

Pyrus  rivularis  Douglas.     Hooker  Fl.  Bor.  Amer.  1,  203.     1839. 

6.  Mains  dawsoniana  Rehder 

Mains  dawsoniana  Rehder.  Sargent,  C.  S.  Trees  and  Shrubs  2,  23.  1913. 
(This  last  was  grown  from  seeds  from  Mains  jusca  collected  in  Oregon  and 
is  described  as  a  hybrid  between  Mains  jusca  and  the  common  apple.) 


'Retired  as  professor  emeritus  September  1,  1926. 

535 


536  BULLETIN  No.  311  [June, 

All  the  older  botanists  include  the  apples  in  the  pear  genus,  Pyrus. 
It  was  not  until  1897  that  Britton  and  Brown  in  their  ''Illustrated 
Flora  of  the  Northern  States  and  Canada"  reinstated  the  genus  Malus, 
which  was  first  instituted  by  Tournefort  in  1700,  and  thus  separated 
the  apples  from  the  pears.  Various  early  attempts  to  separate  apples 
from  pears  were  made,  but  the  characters  upon  which  separation  was 
based  did  not  prove  reliable  in  all  cases.  The  separation  made  by 
Britton  and  Brown  is  based  upon  the  absence  of  grit  cells  in  the  apple 
and  their  presence  in  the  pear.  But  even  this  character  is  said  not  to 
be  entirely  constant. 

Malus  coronaria  is  the  wild  crab  of  the  northeastern  states,  Malus 
angustifolia  is  the  southern  crab,  and  Malus  ioensis  is  native  in  the 
Mississippi  valley.  The  two  latter  have  been  regarded  by  some  as 
varieties  of  coronaria  and  the  similarities  are  such  that  there  is  good 
reason  for  assuming  close  relationship.  Malus  soulardi  has  been  thought 
to  be  a  hybrid  between  Malus  ioensis  and  the  common  apple,  but  many 
crabs  having  large  fruits  have  been  found  in  crab  thickets  in  widely 
separated  localities  along  streams  of  the  Mississippi  valley,  just  as  the 
Soulard  was  found.  Most  of  these  localities  are  distant  from  cultivated 
orchards  and  the  chances  of  cross-pollination  seem  remote.  Some  of 
the  wild  crabs  found  in  thickets,  notably  the  Mercer  County  Crab 
found  by  the  late  N.  K.  Fluke  of  Davenport,  Iowa,  have  fruits  larger 
than  those  of  the  Soulard  Crab.  All  have  their  individual  character- 
istics and  they  are  widely  different  the  one  from  the  other.  A  number 
of  these  crabs  have  been  known  for  many  years,  and  from  the  fact  that 
neither  Soulard  nor  any  of  its  type  have  found  place  with  orchardists 
or  nurserymen  must  be  accepted  as  proof  that  behavior  has  not  con- 
firmed the  numerous  flattering  notices  that  have  been  published  con- 
cerning them. 

All  crab  species  enumerated  are  represented  in  the  Station  col- 
lection of  breeding  material  and  all  have  been  used  as  parents  in 
crosses. 

The  amount  of  work  done,  the  number  and  variety  of  the  crosses 
made,  is,  perhaps,  not  sufficient  to  form  a  perfectly  stable  basis  upon 
which  to  found  judgment  as  to  the  breeding  possibilities  of  these  na- 
tive crabs;  however,  it  is  proposed  to  bring  together  in  this  paper,  for 
such  value  as  they  have,  the  results  of  all  crosses  made  that  involve 
native  crabs  as  parents. 

1.  Malus  coronaria  (L)  Mill. 

This  native  crab  of  the  northeastern  states  is  represented  in  the 
Station  collection  by  only  one  small  tree;  it  is  on  Doucin  stock,  grown 
in  a  10-inch  pot,  was  grafted  February  24,  1911,  and  has  been  forced 
each  spring  in  the  greenhouse.  The  first  flowers  were  produced  in 
1914;  it  did  not  flower  in  1915  but  bore  a  small  number  of  blossoms  in 


NATIVE  CRABS:   THEIR  BEHAVIOR  IN  BREEDING  537 

each  of  the  three  following  years.     The  flowers  produced  were  all 
hand-pollinated. 

Mains  coronaria  as  the  Female  Parent 

Beginning  in  1924,  6  flowers  were  pollinated  by  pollen  from  Yellow 
Transparent  and  25  flowers  by  pollen  from  Oldenburg.  From  the 
pollinations  by  Oldenburg  2  fruits  matured;  these  fruits  contained  7 
seeds,  2  of  which  germinated,  but  the  seedlings  were  extremely  weak 
and  both  died  soon  after  appearing  above  ground.  Thus  these  two 
crosses  of  1914  failed. 

In  1916,  3  crosses  were  made;  5  flowers  pollinated  by  Stayman 
Winesap  and  4  pollinated  by  Akin  failed  entirely.  Pollen  of  Delicious, 
used  on  14  flowers,  yielded  3  mature  fruits  which  contained  9  seeds,  3 
of  which  germinated.  The  three  seedlings  were  planted  in  the  nursery. 
At  the  close  of  1917  two  of  the  seedlings  were  living,  one  graded  as 
fair  and  one  as  poor.  Both  seedlings  were  alive  in  the  fall  of  1918; 
the  one  graded  as  fair  in  1917  had  improved  and  was  graded  as  good, 
the  one  rated  as  poor  remained  poor.  In  1919  both  graded  as  poor. 
In  subsequent  years  they  maintained  the  same  grade  with  scarcely 
perceptible  growth  and  finally  in  1924,  the  eighth  year  from  seed,  both 
died.  These  trees  from  the  time  of  germination,  were  plainly  deficient 
in  vitality,  but  they  continued  to  live  until  during  the  eighth  year. 

In  1917  pollen  of  Jonathan  was  applied  to  stigmas  of  15  flowers, 
and  5  fruits  containing  13  developed  seeds  were  matured.  Of  the  13 
seeds  7  germinated  and  6  seedlings  survived  the  first  season;  1  graded 
as  fair  and  5  as  poor.  In  the  fall  of  1919  all  were  living  and  were 
graded  as  in  1918.  In  1920,  2  graded  as  fair  and  4  as  poor.  In  1921 
one  died;  one  of  those  remaining  was  fair  and  4  were  poor.  The  next 
year  another  died  and  the  4  remaining  all  graded  as  poor.  In  1923 
one  died ;  2  of  those  surviving  were  graded  poor  and  1  fair.  In  1924 
two  seedlings  were  living,  both  graded  as  poor.  At  the  close  of  the 
season  of  1925  only  one  seedling  was  living.  This  tree,  at  the  end  of 
its  eighth  year  measured  4  feet  1  inch  high,  had  a  spread  of  4  feet  2 
inches,  a  trunk  diameter  of  1.1  inches,  and  was  graded  as  poor. 

One  other  cross  was  made  in  the  greenhouse  in  1918  in  which 
5  flowers  of  M.  coronaria  were  pollinated  by  pollen  of  Twenty  Ounce. 
No  fruits  matured. 

Thus  the  net  result  from  the  use  of  pollen  of  seven  varieties  on  an 
aggregate  of  74  flowers  of  M .  coronaria  is  one  feeble  seedling  from  the 
1917  cross  by  Jonathan  that,  from  its  appearance,  may  be  with  cer- 
tainty predicted  to  die  within  the  course  of  the  next,  its  ninth  year 
from  the  seed. 

All  seedlings  from  crosses  in  which  M.  coronaria  was  the  female 
parent  have  been  characterized  by  extreme  debility;  from  the  time  of 
first  appearance  none  gave  any  promise  of  living  to  fruiting  maturity, 


538  BULLETIN  No.  311  [June, 

and  the  wonder  is  that  any  of  them  lived  as  long  as  they  did.  It  is  of 
course  possible  that  should  a  large  number  of  seedlings  be  grown,  in- 
dividuals possessed  of  reasonable  vitality  might  appear,  but  from  ex- 
perience thus  far  gained  it  appears  that  want  of  vitality  in  seedling 
progeny  is  a  complete  bar  to  improvement  in  apple  varieties  thru  use 
of  M.  coronaria  as  the  female  parent  in  crosses. 

Record  of  these  crosses  in  which  M.  coronaria  was  the  female 
parent  is  given  in  tabular  form  in  Table  1. 

Mains  coronaria  as  the  Male  Parent 

The  same  tree  that  was  used  as  .the  female  parent  in  the  crosses 
above  mentioned  supplied  pollen  which  was  used  on  34  flowers  of  6 
orchard  varieties  and  1  crab.  The  pollen  applied  to  stigmas  of  5 
flowers  of  Yellow  Transparent,  5  flowers  of  Akin,  and  4  flowers  of 
Winesap  in  1914,  failed  entirely;  no  fruits  developed. 

In  1916  pollen  was  used  on  8  flowers  of  Stayman  Winesap  and 
this  also  failed.  In  1917,  4  flowers  of  M.  soulardi  pollinated  by  M. 
coronaria  pollen  failed.  Two  flowers  of  Grimes  supplied  with  coronaria 
pollen  produced  one  fruit  which  contained  3  seeds.  Two  of  the  seeds 
were  planted;  both  germinated  and  one  seedling  lived  to  be  planted 
in  nursery.  This  seedling  is  still  living,  has  grown  with  reasonable 
vigor,  and  promises  to  live  to  fruiting  maturity.  At  the  end  of  its 
eighth  year,  1925,  the  tree  stands  4  feet  4  inches  high,  has  a  spread 
of  7  feet  8  inches,  and  a  trunk  diameter  of  1.1  inches.  In  1918,  6 
flowers  of  Twenty  Ounce  wrere  pollinated  by  pollen  of  M.  coronaria 
and  1  fruit  matured  but  it  contained  no  viable  seeds.  Thus  the  results 
for  this  group  of  crosses  in  which  pollen  of  M.  coronaria  was  used  on 
6  varieties  and  1  crab  and  involving  34  pollinations  and  the  production 
of  2  fruits,  is  one  seedling  of  the  cross  on  Grimes,  wrhich  is  now  eight 
years  old  and  will  probably  reach  fruiting  maturity. 

The  record  of  this  group  is  given  in  Table  2. 

2.  Mains  angustifolia  (Ait.)  Michx. 

This  species,  known  as  the  Narrow-Leaved  Crab  or  the  Crab  of 
the  South,  has  been  given  what  may  serve  as  a  fair  trial  in  breeding 
and  has  met  with  practical  failure.  This  failure  may  be  ascribed  to 
low  vitality.  Growth  of  scions  used  in  grafting  has  been  in  all  cases 
slow  and  feeble,  and  most  grafts  have  died  within  one  or  two  years. 

The  first  scions  of  the  species  were  received  in  January,  1907,  but 
they  had  been  dried  in  transit  and  after  storage  under  proper  condi- 
tions only  one  scion  appeared  to  survive;  this  was  root-grafted  on 
apple  seedling  stock  in  March.  The  scion  made  a  slow,  feeble  start, 
was  noted  as  living  on  July  20,  but  died  before  the  end  of  the  season. 
Other  scions  were  received  in  January,  1908,  and  on  the  17th  of  that 
month  10  root-grafts  on  seedling  stocks  were  made.  In  the  spring  10 


1928} 


NATIVE  CRABS:   THEIR  BEHAVIOR  IN  BREEDING 


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540  BULLETIN  No.  311  [June, 

top-grafts  were  made  from  the  remainder  of  the  scion  wood  on  a  small 
tree  of  Sops  of  Wine. 

The  root  grafts  were  planted  in  the  nursery  in  early  spring.  In 
the  fall  of  1908,  when  lifted  for  winter  storage,  three  of  the  scions 
were  living;  they  were  again  planted  in  the  spring  of  1909  and  started 
feeble  growth,  but  all  were  dead  before  the  end  of  the  season.  Of  the 
top-grafts,  6  started  growth  in  1909  and  were  living  on  July  10,  but 
the  growth  made  was  small  and  weak;  all  were  dead  when  examined 
October  4,  1910. 

Death  of  these  grafts  eliminated  the  species  from  the  collection. 

Again  in  1912  scions  were  obtained,  and  on  January  10  ten  scions 
were  grafted  as  root-grafts  on  apple  seedlings  and  two  scions  were 
worked  as  top-grafts  on  Paradise  stocks  in  pots.  Most  of  these  grafts 
started  and  made  feeble  growth,  but  none  endured  beyond  the  third 
year. 

In  1914  scions  were  inserted  on  potted  Doucin  stocks  for  use  in 
the  greenhouse.  One  of  these  grafts  flowered  sparingly  in  March, 
1918.  Pollen  of  Twenty  Ounce  was  used  on  25  flowers  and  9  flowers 
were  pollinated  by  Fameuse.  From  the  Twenty  Ounce  pollinations  2 
fruits  and  from  the  Fameuse  pollinations  1  fruit  matured.  The  average 
of  these  fruits  weighed  16  grams,  measured  27  mm.  in  vertical 
diameter,  33  mm.  in  transverse  diameter,  and  contained  6%  seeds. 

The  two  fruits  from  the  cross  by  Twenty  Ounce  contained  13 
seeds,  8  of  which  germinated,  and  3  seedlings  lived  to  be  planted  in 
nursery.  These  seedlings  were  very  weak;  two  of  them  died  during  the 
second  year  and  the  remaining  one  in  the  third  year. 

The  one  fruit  from  the  cross  by  Fameuse  contained  6  seeds,  5  of 
which  germinated,  and  5  seedlings  were  planted  in  nursery.  Two  of 
these  died  the  first  year,  2  the  second  year,  and  1  was  still  living  in 
1925,  at  the  end  of  its  seventh  year. 

This  tree  was  graded  as  fair  in  1925;  it  is  4  feet  6  inches  high, 
has  a  spread  of  2  feet  and  a  trunk  diameter  of  .9  inch.  The  dimensions 
at  the  end  of  the  seventh  year  show  the  slow,  feeble  growth.  The  one 
living  tree  may  survive  until  it  produces  fruit  but  this  is  doubtful. 

Table  3  brings  together  the  record  of  the  two  crosses. 

Mains  angustifolia  as  the  Male  Parent 

Only  one  attempt  to  use  pollen  of  M.  angustifolia  has  been  made. 
Four  flowers  of  Twenty  Ounce  were  pollinated  by  M.  angustifolia  in 
1918,  but  no  fruits  developed. 

From  the  tests  here  recorded  there  is  no  encouragement  that  M. 
angustifolia  can  be  used  with  success  in  breeding;  this  is  chiefly  be- 
cause of  its  slow,  feeble  growth,  and  because  the  seedling  progeny  is  so 
deficient  in  vitality  that  they  cannot  survive  to  fruiting  maturity. 


1928} 


NATIVE  CRABS:   THEIR  BEHAVIOR  IN  BREEDING 


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542  BULLETIN  No.  311  [June, 

3.  Mains  ioensis  (Wood)  Britton 

The  Western  Crab-Apple,  or  Prairie  States  Crab,  is  native  in 
Illinois  and  surrounding  states  of  the  Mississippi  valley,  and  is  repre- 
sented in  the  Station  collection  by  two  trees,  now  eighteen  years  from 
root-grafts  made  in  1908,  that  have  been  bearing  fruit  for  the  past 
twelve  years. 

Mains  ioensis  as  the  Female  Parent 

The  flowers  of  M.  ioensis  have  been  pollinated  in  five  different 
years  by  pollen  from  six  orchard  varieties  and  each  cross  has  matured 
some  fruit.  The  percentages  of  success  in  fruit  production  have 
ranged  from  18.37  for  a  1915  cross  by  Collins  to  49.18  for  the  1921 
cross  by  Rome.  The  other  varieties  used  as  pollen  parents  are  Jona- 
than, Wealthy,  Pewaukee,  and  Ben  Davis.  The  total  of  pollinations 
made  is  469  and  the  total  of  fruits  matured  is  181,  38.59  percent  of  all 
pollinations  being  successful. 

It  may  be  stated  here  that  the  average  success  percentage  for  all 
crosses  that  have  been  attempted  in  the  apple-breeding  work  is  ap- 
proximately 25.  For  the  group  under  consideration  four  of  the  crosses 
have  success  percentages  far  above  this  average,  while  two  of  the 
crosses  fall  somewhat  below. 

The  success  percentage  for  the  group  is  sufficiently  above  the 
general  average  to  place  this  species  in  the  class  of  what  may  be 
called  good  breeders,  at  least  so  far  as  fruit  production  is  concerned, 
but  it  should  be  kept  in  mind  that  the  ultimate  success  of  a  cross  in- 
volves other  things  than  fruit  production.  Hybrid  fruits  must  contain' 
seeds ;  seeds  must  have  power  to  germinate ;  and  seedlings  must  have 
the  vigor  that  will  insure  production  of  other  fruits  with  viable  seeds 
from  which  may  come  the  next  generation. 

Seed  Production. — The  181  fruits  from  the  six  crosses  contained 
1,049  apparently  good  seeds,  or  5.79  to  each  fruit.  For  the  different 
crosses  the  seed  production  ranged  from  4.26  to  each  fruit  for  the  15 
fruits  of  the  Wealthy  cross,  to  6.82  seeds  to  each  fruit  for  the  35  fruits 
of  the  Ben  Davis  cross.  The  seed  average,  as  ascertained  for  312  open- 
pollinated  fruits  of  this  species,  was  4.19  seeds  to  each  fruit;  hence 
the  average  attained  in  these  crosses  may  be  regarded  as  good  for 
fruits  of  the  crab  class. 

Germination. — Of  the  total  of  1,049  seeds  planted  469,  or  44.73 
percent,  germinated.  For  the  different  crosses,  the  one  by  Rome  had 
the  lowest  percentage;  of  192  seeds  planted  only  14,  or  7.29  percent, 
germinated.  Seeds  of  the  cross  by  Pewaukee  had  the  highest  percent- 
age; of  207  seeds  131,  or  63.28  percent,  germinated. 

Endurance  of  Seedlings. — In  this  group  of  crosses  in  which  M. 
ioensis  was  the  female  parent  there  was  a  considerable  number  of 
seedlings  so  deficient  in  vitality  that  they  died  before  the  time  for 


NATIVE  CRABS  :   THEIR  BEHAVIOR  IN  BREEDING  543 

transfer  to  nursery.  Of  the  469  seedlings  that  appeared  above  ground, 
368  were  planted  in  nursery.  This  indicated  that  101,  or  21.53  percent 
of  the  seedlings,  died  in  the  first  stage  of  existence.  This  loss  was  very 
unevenly  distributed  among  the  various  crosses  and  ranged  from  a 
loss  of  2  of  31  seedlings,  or  6.45  percent  of  the  Collins  cross  of  1915,  to 
76  of  131  seedlings,  or  58.01  percent  for  the  Pewaukee  cross  of  1917. 
Planting  in  nursery  did  not  end  the  losses;  trees  continued  to  die  at  a 
rapid  rate. 

Of  the  368  seedlings  planted  in  nursery,  179  died  the  first  year, 
75  the  second  year,  and  40  the  first  year  in  orchard.  The  older  seed- 
lings from  the  earlier  crosses  died  in  gradually  decreasing  numbers  in 
following  years.  Seedlings  of  the  last  cross  made,  that  by  Rome  in 
1921,  are  four  years  old  and  have  record  of  only  two  years  in  orchard, 
while  seedlings  of  the  1916  cross  by  Jonathan  are  nine  years  of  age 
and  have  record  of  seven  years  in  orchard.  Total  losses  for  the  six 
crosses  to  the  end  of  the  season  of  1925  were  451,  or  96.16  percent  of 
the  seedlings  produced;  this  leaves  only  18  living  seedlings  distributed 
in  four  crosses.  The  last  of  the  31  seedlings  of  the  earliest  cross  by 
Collins  in  1915  died  during  the  third  year  in  orchard.  The  last  of  100 
seedlings  of  the  Ben  Davis  cross  of  1918  died  in  its  fourth  year  in 
orchard.  It  follows  that  only  the  crosses  of  Jonathan,  Wealthy,  Pe- 
waukee, and  Rome  are  now  represented  by  living  seedlings. 

Details  of  the  passing  out  of  the  seedlings  of  the  crosses  under 
•consideration  are  brought  together  in  Table  4. 

Thus  at  the  end  of  1925  a  fraction  over  96  percent  (96.16)  of  the 
seedlings  were  dead;  all  died  for  the  same  reason — inherent  weakness. 
They  had  not  sufficient  vitality  to  live  and  died  more  or  less  promptly. 

The  present  condition  of  the  remaining  seedlings  may  now  be 
examined. 

The  oldest  cross  represented  is  that  of  Jonathan  made  in  1916. 
This  cross  produced  165  seedlings;  at  the  end  of  1925,  the  ninth  year, 
157,  or  95.15  percent,  had  died  and  8,  or  4.85  percent,  were  living. 
These  8  seedlings  ranged  in  height  from  10  inches  to  6  feet  4  inches 
with  an  average  of  3  feet  2%  inches;  in  spread,  from  0  to  3  feet  2 
inches  with  an  average  of  1  foot  2  inches;  and  in  diameter,  from  .3  inch 
to  .9  inch  with  an  average  of  .5  inch.  Six  of  the  trees  graded  as  poor, 
one  as  fair,  and  one  as  good ;  none  have  flowered.  The  six  trees  graded 
as  poor  are  destined  to  die  soon;  the  other  two  may  possibly  survive 
to  fruit  production,  but  even  the  tree  graded  as  good  shows  its  lack 
of  vitality  in  its  growth  performance  thru  nine  years  of  life. 

The  next  cross  is  that  of  Wealthy  made  in  1917.  Starting  with 
28  seedlings,  produced  during  its  eight  years  of  existence,  25,  or  89.29 
percent,  have  died  and  only  3,  or  10.71  percent,,  survive.  These  range 
in  height  from  1  foot  10  inches  to  14  feet  2  inches,  in  spread  from  1 
foot  4  inches  to  12  feet  6  inches,  and  in  diameter  from  .3  inch  to  3.8 


544 


BULLETIN  No.  311 


[June, 


inches.  Two  of  the  trees  are  graded  as  poor,  one  as  good.  This  one 
good  tree  presents  a  strong  contrast  to  the  two  others.  It  has  made 
vigorous  growth  from  the  beginning.  In  1925,  at  eight  years  of  age. 
its  dimensions  are:  height,  14  feet  2  inches;  spread,  12  feet  6  inches; 
and  diameter,  3.8  inches.  It  is  symmetrical  in  form  and  foliage  and 
general  characteristics  closely  resemble  well-grown  trees  of  the  mother 
parent,  M.  ioensis.  This  tree  flowered  in  1925,  its  eighth  year,  with 
most  flowers  fully  open  on  May  6.  On  April  18  fifty  buds  were 
emasculated  and  two  days  later,  on  April  20,  pollen  of  Wealthy  was 
applied  to  the  stigmas.  The  pollinations  were  26  percent  successful 
and  13  fruits  matured.  Characteristics  of  these  fruits  were  as  fol- 
lows : 


Weight 

Largest  fruit 98.84  grams 

Smallest  fruit 57.44  grams 


Vertical 

diameter 

53  mm. 

45  mm. 


Transverse 
diameter 
62  mm. 
52  mm. 


The  largest  fruit  contained  8  seeds,  the  smallest  2  seeds.  One 
fruit  -had  the  seeds  destroyed  by  insects.  The  other  12  fruits  con- 
tained 49  seeds,  an  average  of  4.08  to  each  fruit. 

In  color  the  fruits  were  self-green,  as  in  the  female  parent;  calyx 
lobes  uniformly  persistent,  as  in  both  parents.  Stems  varied  from 
22  mm.  to  30  mm.  in  length.  Flavor  sharply  subacid,  very  juicy; 
quality  poor,  crab-like.  While  the  hand-pollinated  fruits  were  all 
self-green  as  in  the  female  parent,  there  were  open-pollinated  fruits  on 
the  tree  that  displayed  a  light  red  blush,  which  in  some  instances 
spread  over  half  the  surface  of  the  fruit.  The  blushed  fruits  were 
picked  and  described  October  7.  The  three  specimens  from  which  de- 
scription was  made  averaged  78.22  grams  in  weight,  44  mm.  in  vertical 
diameter,  57  mm.  in  transverse  diameter,  and  contained  5  seeds.  In 
form  the  fruits  were  oblate-roundish.  For  convenience  in  comparing 
weight  and  dimensions  of  the  hybrid  fruits  with  weight  and  dimensions 
of  fruits  of  the  two  parents,  as  determined  from  open-pollinated  fruits 
borne  by  the  plants,  the  data  are  brought  together  here  in  tabular 
form: 

Number 


Average 

Average 

Average 

weight 

vertical 

transverse 

Average 

in 

diameter 

diameter 

seed 

grams 

tn  mm. 

in  mm. 

content 

9.02 

23 

26 

4.19 

97.04 

51 

64 

8.02 

76.64 

49 

56 

4.08 

fruits 
averaged 
Malus  ioensis  ...............  312 

Wealthy  ....................  1013 

Hybrid  fruits  ...............     13 

In  form  the  hybrid  fruits  are  like  the  female  parent;  in  weight 
and  diameters  they  approximate  the  male  parent;  and  in  seed  content 
they  fall  far  below  the  male  parent  and  slightly  below  the  female 
parent.  The  49  seeds  from  the  12  hybrid  fruits  of  this  back  cross 
were  planted  in  December,  1925,  and  the  germination  record,  as  taken 


19281  NATIVE  CRABS:   THEIR  BEHAVIOR  IN  BREEDING  545 

in  April,  1926,  shows  that  31  of  the  seeds  germinated  and  that  26  of 
the  seedlings  lived  to  be  planted  in  nursery.  In  the  fall  of  1926  there 
were  17  seedlings  living;  these  were  taken  up  for  winter  storage,  and 
all  were  again  planted  in  nursery  in  May,  1927.  The  best  one  of  the 
17  seedlings  is  15  inches  high  and  is  graded  as  good;  2  others,  one  10 
the  other  11  inches  high,  are  graded  as  fair;  the  others,  14  in  number, 
are  all  very  small  and  are  graded  as  poor.  From  experience  it  may  be 
predicted  that  the  14  seedlings  now  rated  as  poor  will  die  in  this  or 
the  following  year;  the  2  rated  as  fair  will  linger  for  a  longer  period, 
or  may  even  improve  and  survive  to  fruiting,  and  the  one  individual, 
which,  from  its  evident  vigor,  is  rated  as  good,  should  continue  to  the 
full  development  of  a  normal  apple  seedling. 

The  two  surviving  trees  of  this  cross,  M.  ioensis  X  Wealthy,  that 
are  graded  as  poor,  are  in  the  same  class  with  those  that  have  died. 
They  have  been  deficient  in  vitality  from  the  beginning,  as  is  shown 
by  the  annual  increments,  and  they  are  destined  to  die  within  a  short 
time,  leaving  the  one  tree  that  possessed  vitality  to  grow  and  continue 
producing  fruit  as  the  sole  representative  of  the  cross. 

The  cross  of  Pewaukee,  also  of  1917,  produced  131  seedlings  from 
the  207  seeds  planted,  and  at  the  end  of  1925,  the  eighth  year,  5  were 
living.  Here  the  loss  amounted  to  126  seedlings,  or  96.18  percent  of 
the  number  produced,  and  of  the  5  seedlings  remaining  in  1925  4 
graded  as  poor  and  1  as  fair.  The  growth  increment  of  all  the  trees 
has  been  small  in  each  year,  and  while  the  one  tree  now  graded  as  fair 
may  live  to  fruiting,  the  others  are  not  likely  to  attain  that  end. 

From  the  growth  record  of  1925,  at  the  end  of  the  eighth  year,  it 
is  found  that  the  4  trees  graded  as  poor  have  an  average  height  of 

3  feet,  an  average  spread  of  2  feet  9  inches,  and  an  average  diameter 
of  .5  inch ;  and  that  the  tree  graded  as  fair  is  7  feet  6  inches  high,  has 
a  spread  of  7  feet  2  inches,  and  a  trunk  diameter  of  1.4  inches.    For 
eight-year-old  trees  this  is  a  poor  performance  and  plainly  shows  the 
deficiencies  in  vitality. 

There  remains  the  1921  cross  by  Rome.  This  is  represented  by 
2  seedlings,  all  that  are  living  of  the  14  produced.  The  loss  here  is 
85.70  percent;  4  seedlings  having  died  before  transfer  to  nursery,  4 
during  the  first  year  in  nursery,  and  4  during  the  second  year.  The 
two  remaining  were  graded  as  good;  their  average  height  was  3  feet 

4  inches,  there  was  no  spread,  and  the  average  diameter  was  .45  inch. 
The  next  year,  1924,  the  average  height  was  3  feet  8  inches,  average 
spread  8  inches,  and  average  diameter  .5  inch;  one  graded  as  good  the 
other  as  fair.    For  the  last  year,  1925,  both  trees  graded  as  good,  had 
an  average  height  of  4  feet,  an  average  spread  of  1  foot  6  inches,  and 
an  average  diameter  of  .7  inch.    The  appearance  of  the  two  surviving 
trees  of  this  cross  at  the  end  of  the  fourth  year  suggests  that  they 
may  live  to  fruiting  age  altho  the  growth  performance  indicates  vigor 
less  than  normal. 


546 


BULLETIN  No.  311 


[June, 


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1928}  NATIVE  CRABS:   THEIR  BEHAVIOR  IN  BREEDING  547 

Of  the  18  seedlings  remaining  in  four  of  the  six  crosses  made,  13 
are  graded  as  poor  and  are  quite  certain  to  die  before  fruiting,  as  did 
so  many  others.  Three  seedlings  graded  as  fair,  and  it  may  be  hoped 
rather  than  expected  that  these  survive  to  fruiting  age.  Of  the  3  that 
rate  as  good,  one  has  fruited  and  the  others  will  probably  attain  this 
end  within  one  or  two  years. 

The  record  of  this  group  of  crosses  is  brought  together  in  tabular 
form  in  Table  5. 

Experience  with  these  crosses,  in  which  M.  ioensis  was  the  female 
parent,  does  not  encourage  the  view  that  this  species  of  our  native 
crabs  can  be  successfully  used  as  a  basis  for  the  improvement  of  apple 
varieties.  The  reason  does  not  rest  in  failure  to  produce  fruits  from 
flowers  pollinated,  for  these  crosses  show  that  38.50  percent  of  the 
pollinations  made  were  successful  and  this  is  far  above  the  average 
for  all  crosses.  There  was  no  deficiency  in  seed  production,  for  the 
seed  average  was  5.79  seeds  from  each  fruit;  nor  does  the  difficulty 
lie  with  germination,  for  nearly  45  percent  of  the  seeds  germinated. 
Inspection  of  the  seedlings  at  once  gives  the  reason  for  failure.  In  the 
crosses  made,  vitality  sufficient  for  existence  is  not  transmitted  to  the 
offspring;  the  seedlings  die  immediately  after  germination,  or  they 
make  a  feeble  growth  for  a  few  years  and  then  die  because  they  have 
not  vitality  enough  to  live. 

No  attempts  to  use  M.  ioensis  as  the  male  parent  have  been  made, 
chiefly  because  of  its  late  blooming  habit. 

4.  Mains  soulardi  (Bailey)  Britton 

The  Soulard  Crab  originated  in  the  Mississippi  valley  near  St. 
Louis  more  than  sixty  years  ago.  It  has  been  the  subject  of  much 
discussion,  and  botanists  have  expressed  very  different  views  as  to  its 
proper  position  in  botanical  classification.  It  has  often  been  referred 
to  as  a  hybrid  arising  from  pollination  of  flowers  of  M.  ioensis  by 
pollen  of  the  common  apple,  or  from  flowers  of  M.  coronaria  by  the 
common  apple.  In  1891  Bailey  described  it  and  gave  it  rank  as  a 
new  species — Pyrus  soulardi — in  the  American  Garden.  Britton  and 
Brown  recognized  it,  transferred  it  to  the  genus  Malus,  and  included 
it  in  the  "Illustrated  Flora  of  the  Northern  States  and  Canada"  as 
Malus  soulardi,  in  1897.  In  1898  Bailey  in  his  "Evolution  of  Our 
Native  Fruits"  reverses  his  former  judgment  and  says,  "I  confess  to  a 
belief  that  Pyrus  soulardi  is  not  a  true  species,  but  is  a  hybrid  between 
Pyrus  ioensis  and  the  common  apple,  Malus  mains." 

The  writer  is  content  to  allow  Malus  soulardi  to  stand  as  a  dis- 
tinct species;  at  all  events  it  is  so  distinctly  different  from  any  other 
form  of  Malus  in  the  Station  collection  that  there  is  no  danger  of 
confusing  it  with  any  of  them.  M.  soulardi  is  only  one  of  a  consider- 
able number  of  large-fruited  wild  crabs  that  have  been  discovered  in 


548  BULLETIN  No.  311  [June, 

crab  thickets  in  various  localities  along  the  streams  of  the  Mississippi 
valley.  An  example  of  these  crabs  is  found  in  the  Mercer  County 
Crab,  which  was  discovered  by  the  late  N.  K.  Fluke  of  Davenport, 
Iowa.  This  is  represented  in  the  Station  collection  by  several  trees; 
they  are  quite  different  from  M.  soulardi  in  form  and  size  and  par- 
ticularly in  the  leaves;  the  fruit  is  of  about  the  same  form  and  color 
as  the  fruit  of  M .  soulardi,  but  is  larger.  Thus,  the  average  weight  of 
425  fruits  of  M.  soulardi  is  38  grams,  while  the  average  of  822  fruits 
of  Mercer  County  Crab  is  over  80  grams;  diameters  of  fruits  of  M. 
soulardi  are  34  mm.  vertical  by  41  mm.  transverse,  and  for  the  Mercer 
County  Crab  they  are  47  mm.  vertical  by  59  mm.  transverse. 

M.  soulardi  is  characterized  by  extreme  vigor  of  growth  in  its 
earlier  years,  by  strictly  erect  habit,  which  is  modified  under  heavy 
crops  of  fruit  until  the  trees  spread  widely.  The  leaves  are  large, 
broadly  ovate,  oblong  or  elliptical,  very  dark  green,  and  conspicuously 
rugose. 

Mains  soulardi  as  the  Female  Parent 

This  species  has  been  used  as  the  female  parent  in  26  crosses  with 
13  orchard  varieties  and  3  crab  forms.  Flowers  pollinated  for  all 
crosses  number  575.  Five  crosses,  with  340  pollinations,  were  on  trees 
in  orchard  and  21  crosses,  with  235  pollinations,  were  on  potted  dwarfs 
in  the  greenhouse.  Sixteen  of  the  crosses,  with  283  pollinations,  ma- 
tured no  fruits.  The  10  others,  with  an  aggregate  of  292  pollinations, 
matured  52  fruits,  which  ranged,  in  numbers  to  each  cross,  from  1  to 
19.  It  thus  appears  that  9.04  percent  of  all  pollinations  made  were 
successful  so  far  as  fruit  production  is  concerned.  Of  the  10  crosses 
producing  fruits,  2  had  one  fruit  each,  and  neither  fruit  contained 
seeds;  these  were  both  greenhouse  crosses  of  1916,  one  by  Fanny,  the 
other  one  of  four  crosses  by  Yellow  Transparent.  The  one  fruit  from 
the  greenhouse  cross  by  Winesap  in  1914  contained  3  seeds,  but  these 
did  not  germinate..  The  Oldenburg  cross  in  orchard  in  1915,  from  49 
pollinations,  matured  2  fruits  containing  6  seeds,  3  of  which  germi- 
nated, but  all  three  of  the  seedlings  died  in  the  second  year. 

The  Oliver  cross,  made  in  the  greenhouse  in  1916,  from  6  polli- 
nations matured  3  fruits  containing  5  seeds,  1  of  which  germinated, 
but  the  seedling  died  in  its  second  year. 

The  greenhouse  cross  by  Oldenburg  in  1918  from  22  pollinations 
matured  2  fruits  containing  2  seeds,  1  of  which  germinated.  The  seed- 
ling was  very  weak,  but  lingered  until  in  its  fourth  year,  when  it  died. 

So  there  are  6  crosses  to  be  added  to  the  16  that  failed  to  mature 
any  fruits,  making  22  crosses  that  are  not  represented  by  seedlings. 
There  are  4  crosses  that  now  have  living  seedlings;  these  are  the 
greenhouse  cross  by  Delicious  in  1916,  which,  from  9  pollinations, 
matured  1  fruit  having  3  seeds,  2  of  which  germinated.  One  of  the 
seedlings  died  in  1921  in  its  fifth  year;  the  other  is  still  living  and  in 


1928]  NATIVE  CRABS:   THEIR  BEHAVIOR  IN  BREEDING  549 

1925,  at  the  end  of  its  ninth  year,  it  lacked  1  inch  of  being  6  feet  high, 
had  a  spread  of  4  feet  8  inches,  and  a  trunk  diameter  of  1.2  inches. 
It  was  graded  as  fair  and  may  survive  to  fruiting  age. 

The  Jonathan  cross  made  in  the  greenhouse  in  1917  matured  6 
fruits  from  10  pollinations;  these  contained  12  seeds,  8  of  which  germi- 
nated, and  7  seedlings  were  transferred  to  nursery.  All  these  seedlings 
lived  thru  the  first  year,  but  4  died  in  the  second  year,  1  in  the  fourth 
year,  and  1  in  the  fifth  year,  leaving  1  seedling,  which  in  1925  com- 
pleted its  eighth  year;  it  then  measured  4  feet  8  inches  in  height,  had 
a  spread  of  5  feet  6  inches  and  a  trunk  diameter  of  1.5  inches.  It  is 
graded  as  fair  and  will  possibly  survive  to  fruiting. 

Considering  the  crosses  in  order  of  time,  we  have  next  the  cross 
of  Pewaukee  made  in  the  orchard  in  1917.  In  this  cross  133  pollin- 
ations were  made  and  19  fruits  matured;  thus  14.21  percent  of  the 
pollinations  made  were  successful  in  fruit  production.  The  19  fruits 
contained  55  seeds,  an  average  of  approximately  2.9  seeds  to  each 
fruit,  and  34,  or  61.82  percent,  germinated.  Five  of  the  seedlings  died 
very  soon  after  germination,  so  that  only  29  seedlings  were  transferred 
to  nursery.  The  majority  of  the  seedlings  were  very  weak  and  indi- 
cated by  their  appearance  that  they  were  destined  to  die  long  before 
reaching  fruit  production.  These  seedlings  died  as  follows:  2  the  first 
year  in  nursery,  8  the  second  year,  6  in  the  third  year  or  first  year  in 
orchard,  2  in  the  fourth  year,  1  in  the  fifth  year,  and  2  in  the  sixth 
year;  making  a  loss,  from  the  time  of  removal  to  nursery  to  the  end 
of  the  sixth  year,  of  21  seedlings,  or  72.41  percent  of  the  number 
planted  in  nursery,  and  bringing  the  total  losses,  from  germination  to 
the  end  of  the  sixth  year,  to  26  seedlings,  or  76.24  percent.  All  these 
losses  are  rightly  ascribed  to  inherent  weakness;  the  seedlings  did  not 
have  sufficient  vitality  to  live,  and  passed  out  gradually. 

Of  the  8  seedlings  living  in  1925,  at  the  end  of  the  eighth  year,  4 
are  graded  as  fair  and  4  as  poor.  The  range  in  height  is  from  10  inches 
to  8  feet  10  inches  with  an  average  of  5  feet  3  inches;  the  spread 
ranges  from  4  inches  to  6  feet  8  inches  with  an  average  of  3  feet 
6  inches;  and  the  diameter,  from  .4  inch  to  2.7  inches  with  an  average 
of  1.25  inches.  These  dimensions  for  trees  that  are  eight  years  old 
exhibit  the  extremely  slow  growth  and  absence  of  the  vigor  that 
normal  seedlings  should  have.  The  4  seedlings  rated  as  poor  may 
linger  a  year  or  two  longer,  but  they  are  surely  destined  to  die  before 
producing  fruit.  For  the  4  rated  as  fair  it  may  be  hoped  that  they 
will  live  to  bear  fruit. 

The  last  of  this  group  of  crosses  is  that  of  Oldenburg  on  a  tree  in 
orchard  in  1917.  In  this  case  48  flowers  were  pollinated  and  16  fruits 
matured;  thus  exactly  one-third  of  the  pollinations  were  successful. 
The  16  fruits  contained  35  seeds,  an  average  of  2.18  to  each  fruit;  18 
of  the  seeds,  or  51.43  percent,  germinated.  The  seedlings  exhibited  the 


550  BULLETIN  No.  311  [June, 

same  weakness  that  characterized  the  seedlings  of  other  crosses  in 
this  group  having  M.  soulardi  as  the  female  parent.  Six,  or  one-third, 
of  the  seedlings  died  before  it  was  time  to  transfer  to  nursery ;  and  of 
the  12  removed  to  nursery,  4  died  the  first  year,  3  the  second,  and  1  in 
each  of  the  fourth,  sixth,  and  seventh  years ;  making  a  loss  of  16  seed- 
lings, or  88.88  percent  of  the  number  when  germination  was  com- 
pleted. 

Of  the  two  seedlings  that  survived  in  1925,  at  the  end  of  the 
eighth  year,  one  was  2  feet  high,  had  a  spread  of  6  inches,  and  a  trunk 
diameter  of  .4  inch;  the  other  was  5  feet  8  inches  high,  had  a  spread 
of  2  feet  5  inches,  and  a  trunk  diameter  of  .7  inch.  Both  were  rated 
as  poor  and  altho  one  is  nearly  three  times  as  tall  as  the  other,  has 
nearly  five  times  the  spread,  and  exceeds  it  in  trunk  diameter  by  75 
percent,  it  is  not  expected  that  either  will  live  to  bear  fruits. 

To  summarize  what  has  been  done  in  the  use  of  M .  soulardi  as  a 
female  parent. 

Twenty-six  crosses  were  made  with  13  orchard  varieties  and  3 
crab-like  species  of  Malus  in  five  different  years.  Some  of  the  crosses 
were  made  in  the  greenhouse  and  some  on  trees  in  orchard,  the  whole 
involving  575  pollinations  and  yielding  52  fruits.  Sixteen  of  the 
crosses  failed  in  fruit  production,  and  of  the  10  crosses  maturing  fruits 
6  failed  because  the  fruits  were  seedless  or  the  seeds  did  not  germinate. 
The  52  fruits  contained  121  seeds  and  of  these  67,  or  55.37  percent, 
germinated  and  54  seedlings  lived  to  be  planted  in  nursery.  Weak 
seedlings  continued  to  die,  and  in  the  fall  of  1925  only  12  seedlings  of 
4  crosses  remained  alive.  One  of  these  seedlings  is  nine  years  old  and 
11  are  eight  years  old.  Losses  from  the  time  of  germination  aggregate 
82  percent.  The  12  living  seedlings  divide  equally  as  to  grade,  6  are 
rated  poor  and  6  fair.  Those  rated  as  poor  indicate,  by  their  appear- 
ance, that  they  will  soon  die;  certainly  none  of  them  can  live  to  pro- 
duce fruit.  The  6  better  trees  now  graded  as  fair  may  survive  to 
fruiting,  altho  even  the  best  individual  has,  by  its  growth  performance, 
exhibited  vitality  much  below  that  possessed  by  normal  seedlings. 
Thus  of  67  seedlings  produced  in  this  group  of  crosses,  6  have  a  pos- 
sible chance  of  survival  to  fruit  production. 

The  records  of  the  behavior  of  all  crosses  having  M.  soulardi  as 
the  female  parent  are  brought  together  in  Table  6. 

No  attempt  has  been  made  to  use  M.  soulardi  as  the  male  parent. 

The  Mercer  County  Crab 

This  Mercer  County  Crab  is  not  given  specific  rank,  but  it  is  of 
the  type  of  M .  soulardi  and  without  doubt  is  closely  related  to  it,  as  it 
originated  in  the  same  way  and  is  native  in  the  same  region.  Breeding 
tests  with  this  crab  may  follow  those  given  for  M .  soulardi. 

The  Mercer  County  Crab  was  used  as  the  female  parent  in  8 


NATIVE  CRABS  :   THEIR  BEHAVIOR  IN  BREEDING 


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552  BULLETIN  No.  311  [June, 

crosses  by  5  orchard  varieties  and  1  crab-form,  all  made  in  the  green- 
house in  the  years  1913  to  1918. 

The  1913  cross  by  Yellow  Transparent  yielded  4  fruits  from  11 
pollinations;  thus  36.36  percent  of  the  pollinations  were  successful  in 
fruit  production.  The  4  fruits  contained  14  seeds,  an  average  of  3.5 
to  each  fruit.  Nine  of  the  seeds  germinated;  3  seedlings  lived  to  be 
planted  in  nursery,  but  the  last  one  died  in  the  fourth  year. 

A  1914  cross  by  Grimes  matured  1  fruit  from  9  pollinations;  this 
fruit  contained  3  seeds,  1  of  which  germinated,  but  the  seedling  did  not 
live  to  be  planted  in  nursery.  One  other  cross,  that  by  Fanny  in  1917, 
matured  1  fruit  from  23  pollinations;  this  fruit  also  contained  3  seeds, 
but  none  germinated.  The  other  5  crosses  failed  to  produce  fruits. 

The  total  number  of  pollinations  in  the  8  crosses  was  81.  Three 
of  the  crosses  matured  6  fruits,  representing  7.4  percent  of  the  pollin- 
ations. The  6  fruits  contained  20  seeds,  10  of  which  germinated,  but 
only  3  seedlings  lived  to  be  planted  in  nursery  and  the  last  of  these 
died  before  the  end  of  the  fourth  year. 

The  Mercer  County  Crab  was  used  as  the  male  parent  in  5  green- 
house crosses,  4  on  orchard  varieties  and  1  on  the  crab-form  M.  ringo. 
The  crosses  on  orchard  varieties  all  failed,  but  the  one  on  the  crab 
was  47.83  percent  successful,  11  fruits  maturing  from  23  pollinations. 
The  11  fruits  contained  25  seeds,  13  of  which  germinated.  Seven  of  the 
seedlings  were  planted  in  nursery ;  3  of  these  died  the  first  year,  1  the 
second,  and  1  the  third  year. 

The  two  remaining  trees,  now  eleven  years  old,  are  widely  dif- 
ferent. One  of  these  trees  has  been  weak  from  the  beginning  and  its 
growth  increments  are  very  small;  it  is  now  3  feet  8  inches  in  height, 
spreads  4  feet  2  inches,  and  has  a  trunk  diameter  of  .8  inch ;  it  belongs 
in  the  class  of  other  seedlings  that  have  died  and  will  probably  end  its 
struggle  for  existence  this  year.  The  other  seedling  has,  from  the  time 
of  germination,  given  evidence  of  the  possession  of  vitality ;  growth 
has  been  good  and  it  is  now  10  feet  5  inches  high,  spreads  12  feet  2 
inches,  and  has  a  trunk  diameter  of  6  inches.  The  tree  is  symmetrical, 
somewhat  spreading  as  are  both  its  parents.  The  branches  are  quite 
smooth  and  the  bark  dark  reddish-brown,  as  in  M.  ringo.  It  has  not 
yet  fruited,  but  is  expected  to  produce  flowers  either  this  year  or  next. 
On  the  expected  death  of  the  weak  tree,  this  vigorous,  well-developed 
tree  will  stand  as  the  only  representative  of  a  cross  having  the  Mercer 
County  Crab  as  a  male  parent. 

5.   Mains  fusca  (Rafin.)  Schneider 

M.  jusca  is  the  Oregon  Crab  Apple,  native  on  the  Pacific  Coast 
from  Sonoma  county,  California,  northward  along  the  coast  thru  Ore- 
gon and  Washington  to  Alaska.  It  appeared  for  many  years  under  the 
name  Pyrus  rivularis,  as  published  by  Douglas  in  Hooker's  "Flora  of 


19281  NATIVE  CRABS  :   THEIR  BEHAVIOR  IN  BREEDING  553 

North  America,"  but  this  name  was  finally  superseded  by  fusca  as  be- 
ing an  earlier  name  applied  by  Rafinesque. 

This  western  species  is  totally  different  from  the  native  species 
growing  east  of  the  Rocky  Mountains.  Its  affinities  are  nearer  to 
Siberian  species  than  to  other  North  American  species.  The  tree  is 
said  to  grow  from  15  to  25  feet  high,  but  frequently  takes  the  form  of 
a  many-stemmed  shrub.  The  leaves  are  small  and  of  various  forms; 
many  are  ovate  in  outline,  acute  or  acuminate,  often  more  or  less 
lobed;  margins  are  sharply  serrate,  or  on  some  leaves  crenate.  As 
grown  at  this  Station  from  scions  received  from  the  Arnold  Arboretum, 
the  tree  is  decidedly  dwarf  in  appearance  and  of  very  slow  growth. 
One  tree  from  a  root-graft  made  in  January,  1908,  as  measured  in  the 
fall  of  1924,  when  seventeen  years  old,  was  9  feet  6  inches  high,  had  a 
spread  of  5  feet  4  inches,  and  a  trunk  diameter  of  2.9  inches.  Another 
free  from  a  top-graft  inserted  April  7,  1908,  on  a  Virginia  Crab  seed- 
ling measured,  in  October,  1925,  at  eighteen  years  from  graft,  13  feet 

2  inches  high,  had  a  spread  of  11  feet,  and  a  trunk  diameter  of  5.8 
inches.    In  general  the  direction  of  branches  is  erect,  becoming  more 
spreading  with  age. 

This  species  flowers  from  terminal  mixed  buds  and  to  some  extent 
from  lateral  buds  on  terminal  shoots.  The  inflorescence  is  corymbose, 
with  from  9  to  13  flower  buds  in  each  cluster.  In  most  buds  the  axis 
elongates  somewhat,  giving  the  cluster  a  racemose  appearance.  Indi- 
vidual flower  buds  are  small,  white,  and  tinged  pink.  Flowers  expand 
from  13  to  18  mm.  and  are  pure  white.  Pedicels  are  slender,  16  mm.  to 
20  mm.  long,  each  with  1  to  3  linear  bracts;  slightly  pubescent,  as  is 
also  the  ovary  and  the  exterior  surface  of  the  small,  obtusely  tri- 
angular calyx  lobes.  Petals  are  5  to  7  mm.  long  by  3  to  5  mm.  broad, 
mostly  rounded,  and  inclined  to  be  cordate,  claw  very  short.  Stamens 
16  to  20,  filaments  slender,  3  to  5  mm.  long;  anthers  large,  plump, 
creamy  white.  Pollen  grains  large,  elliptical,  almost  white.  Styles 

3  or  4,  slender,  4  mm.  long,  connate  half  the  length,  glabrous,  tips 
compressed.    Stigmas  oval  or  elliptical.  Ovary  3-  or  4-celled.  Flowers 
fragrant.    Fruits  small,  oblong,  cylindrical  or  ovoid  in  form.    Of  22 
fruits  weighed  and  measured,  the  average  wreighs  one-half  gram;  the 
average  vertical  diameter  is  10  mm.,  the  transverse  diameter  9  mm. 
The  color  is  self-yellow  or  with  a  bronze  or  red  blush  on  one  side. 
Each  fruit  has  either  3  or  4  carpels  with  2  ovules  in  each,  but  the 
average  of  developed  seeds  is  1.32  to  each  fruit,  the  lowest  seed  aver- 
age of  any  species  of  Malus  examined.  The  seeds  are  very  small,  only 
two  species  have  seeds  of  less  size,  namely,  M .  sargenti  and  M .  toringo. 

Malus  fusca  as  the  Female  Parent 

M.  fusca  has  been  used  as  the  female  parent  in  3  crosses.  In  1916 
Jonathan  pollen  was  used  to  pollinate  117  flowers;  11  fruits,  repre- 


554  BULLETIN  No.  311  [June, 

senting  9.4  percent  of  the  pollinations,  matured.  These  11  fruits  con- 
tained 13  seeds,  3  of  which  germinated,  and  the  seedlings  completed 
their  ninth  year  in  1925.  In  the  growth  record  for  1925  the  trees  have 
dimensions  and  ratings  as  follows: 

Cross  No.                         Height  Spread  Diameter  Rated  as 

11383-1 2  ft.    2  in.  2  ft.  2  in.  .9  in.  "poor" 

11383-2 8ft.    Sin.  6  ft.  8  in.  2.7  in.  "good" 

11383-3-2 9  ft.  11  in.  9  ft.  4  in.  3.0  in.  "good" 

For  trees  nine  years  old  the  dimensions  are  small,  and  the  larger 
tree  is  over  four  times  the  height  of  the  smaller  and  has  more  than 
three  times  the  diameter.  With  most  crosses  an  individual  but  little 
over  2  feet  tall  at*the  end  of  nine  years  would  be  looked  upon  as 
meaning  the  end  of  its  existence,  but  in  this  cross  the  usually  dwarf 
growth  of  the  female  parent  should  be  considered,  and  as  the  smallest 
tree  of  this  group  has  appearance  of  health,  it  may  be  expected  that 
all  of  the  trees  will  live  to  produce  fruit.  The  diminutive  size  may  be 
ascribed  to  inheritance  of  the  dwarf  habit  of  the  female  parent. 

In  the  following  year,  1917,  Oldenburg  pollen  was  applied  to 
stigmas  of  121  flowers,  and  one  fruit  -matured.  This  fruit  contained 
one  seed;  the  seed  germinated,  but  the  seedling  died  before  time  to 
transplant  to  nursery.  Thus  this  cross  failed  entirely. 

Again  in  1921  pollen  of  Rome  was  used  to  pollinate  57  flowers  of 
M.  fiisca;  6  fruits  matured,  representing  10.53  percent  of  the  pollin- 
ations. The  six  fruits  contained  8  seeds,  only  2  of  which  germinated. 
The  two  seedlings  were  planted  in  nursery,  and  one  of  them  died  be- 
fore the  end  of  the  first  season.  The  remaining  seedling  is  now  four 
years  old,  has  been  two  years  in  orchard,  and  in  the  growth  record  of 
1925  is  recorded  as  2  feet  2  inches  in  height,  having  a  spread  of  3  feet, 
a  trunk  diameter  of  .8  inch,  and  is  graded  as  good. 

Thus  at  the  end  of  1925  there  were  in  orchard  4  seedlings  from 
crosses  in  which  M.  fusca  was  the  female  parent — 3  from  the  1916 
cross  by  Jonathan  and  1  from  the  1921  cross  by  Rome.  None  of  these 
seedlings  have  fruited;  they  are  all  small  and  more  or  less  dwarfed  in 
appearance,  but  all  are  healthy  and  it  is  expected  that  they  will  live 
to  bear  fruit.  The  use  thus  far  made  of  M.  fusca  as  a  female  parent 
is  too  limited  to  serve  as  a  basis  upon  which  to  form  judgment  as  to 
the  real  value  of  the  species  for  breeding  purposes,  but  from  the  low 
percentage  of  pollinations  maturing  fruit,  the  low  seed  content  of  the 
hybrid  fruits,  and  the  slow  growth  of  the  seedlings,  there  is  little  to 
encourage  belief  in  successful  use  of  this  species. 

The  use  of  M.  fusca  as  the  male  parent  has  not  been  attempted. 

6.  Mains  dawsoniana  Rehder 

This  species  was  described  in  1913  as  a  hybrid  between  M.  fusca 
and  the  common  apple.  The  tree  was  grown  at  the  Arnold  Arboretum 
from  seeds  of  M.  fusca  collected  by  C.  G.  Pringle  in  Oregon  in  1881. 


number 

weight 

vertical 

transverse 

of 

in 

diameter 

diameter 

good  seeds 

grams 

in  mm. 

in  mm. 

2.00 

.508 

9.26 

8.69 

2.90 

11.74 

31.73 

26.36 

1928]  NATIVE  CRABS:   THEIR  BEHAVIOR  IN  BREEDING  555 

The  general  habit  of  growth  resembles  that  of  M.  fusca,  but  the 
tree  is  much  more  vigorous,  has  a  tendency  to  the  production  of 
numerous  branches,  and  thus  forms  a  very  dense  crown.  Leaves  are 
dark  green,  ovate  or  oval  in  form,  larger  than  leaves  of  M.  fusca  and 
less  inclined  to  be  lobed;  they  are  pubescent  when  young,  becoming 
glabrous  when  mature.  Flowers  are  borne  from  terminal  buds  of 
terminal  twigs  and  spurs.  Flowers  range  from  5  to  13  to  the  cluster, 
but  usually  the  number  is  from  8  to  10 ;  they  are  pure  white,  and  ex- 
pand from  32  to  35  mm.  as  compared  with  13  to  18  mm.  for  flowers  of 
M.  fusca.  Fruits  of  M .  dawsoniana  are  considerably  larger  than  fruits 
of  M.  fusca  and  different  in  form,  being  oval-oblong  or  often  obovate- 
oblong.  Differences  in  fruits  of  the  two  species  can  be  most  clearly 
shown  by  arranging  available  records  in  tabular  form  as  below. 

Average         Average          Average         Average 
Number 

of 
fruits 

841  M.  fusca 72 

842  M.  dawsoniana..  379 

Calyx  lobes  of  M .  fusca  are  deciduous  in  all  fruits.  M.  dawsoniana 
has  persistent  calyx  lobes  in  nearly  all  fruits,  but  an  occasional  fruit 
is  found  that  has  the  calyx  lobes  deciduous  in  the  regular  manner. 
Color  of  the  fruit  of  M.  dawsoniana  as  grown  here  is  usually  a  green- 
ish-yellow and  there  are  occasional  fruits  having  a  bright  red  blush  on 
one  cheek;  this  feature,  however,  appears  to  vary  in  different  seasons, 
being  sometimes  rare  and  in  some  seasons  common. 

Only  one  cross  has  been  attempted  with  M.  dawsoniana  as  the 
female  parent.  This  was  in  1918  when,  on  May  6,  69  flowers,  which 
had  been  emasculated  on  May  3,  were  pollinated,  with  Jonathan  pollen. 
No  fruits  developed. 

Self-Pollinations  of  Apple  Forms 

Native  Crabs. — It  has  been  the  intention  to  self-pollinate  some 
flowers  on  each  of  the  apple  forms  used  in  the  breeding  work  in  order 
to  test  their  relative  self-sterility  pr  self-fertility.  This  work  has  been 
done  as  opportunity  offered;  it  has  not  yet  included  all  forms  and  is 
not  nearly  so  extensive  as  is  desired.  Some  flowers  have  been  self- 
pollinated  on  each  of  five  of  the  species  of  native  crabs,  but  the  Pacific 
Coast  species,  M.  fusca,  has  not  been  tested,  chiefly  because  it  flowers 
much  later  than  other  forms  and  attention  to  the  blossoms  at  the 
proper  time  has  been  crowded  out  by  other  work. 

Summarizing  the  self-pollinations  made  on  the  five  native  crabs, 
it  appears  that  an  aggregate  of  840  flowers  were  self-pollinated  in 
eleven  of  the  thirteen  years  of  the  period  1914  to  1926. 


556  BULLETIN  No.  311  [June, 

M.  coronaria  from  4  self-pollinations  .in  1918  developed  3  fruits 
containing  9  seeds,  none  of  which  germinated,  and  the  72  self-pollin- 
ations of  1926  matured  no  fruits. 

On  M.  ioensis  the  287  self-pollinations  were  distributed  over  four 
years;  from  the  114  self-pollinations  of  1917  one  fruit  containing  2 
seeds  developed,  and  from  the  47  self-pollinations  in  1926  two  fruits 
with  3  seeds  matured,  but  none  of  these  seeds  germinated. 

On  M.  soulardi  264  self-pollinations  were  made  in  eight  efforts  in 
seven  years,  but  no  fruits  matured,  arid  there  was  the  same  complete 
failure  for  92  self-pollinations,  distributed  over  three  years,  on  the 
Mercer  County  Crab. 

Thus  these  four  species,  coronaria,  ioensis,  soulardi,  and  the  Mer- 
cer County  Crab,  tested  thru  712  self-pollinations,  register  complete 
failure  to  produce  viable  seeds  and  are  therefore  completely  self-sterile 
so  far  as  efforts  thus  far  made  are  concerned. 

The  remaining  species,  M.  dawsoniana,  saves  the  whole  effort  in 
self-pollination  of  native  crabs  from  complete  failure  by  the  produc- 
tion 'of  one  seedling.  The  48  self-pollinations  of  1925  matured  no 
fruit;  the  73  self-pollinations  of  1926  matured  2  fruits;  one  of  these 
contained  1  seed,  which  did  not  germinate,  the  other  contained  3  seeds, 
one  of  which  germinated.  This  seedling  from  seed  planted  in  De- 
cember, 1926,  and  stored  in  a  pit  thru  the  winter,  appeared  above 
ground  on  March  31  and  at  the  time  of  shifting  to  the  nursery  on  June 
6,  1927,  while  not  so  tall  as  many  seedlings  in  groups  from  crosses, 
was  healthy  and  appeared  to  possess  vigor  equal  to  that  of  its  parent. 

This  seedling  will  be  watched  with  interest  as  being  the  only 
product  from  the  self-pollination  of  a  native  crab. 

This  test  of  self-fertility  leads  to  the  conclusion  that  native  crabs 
are  self-sterile  to  such  degree  as  to  constitute  an  effective  bar  to  the 
attainment  of  a  generation  of  seedlings  from  self-pollinations;  and 
yet,  having  observed  the  wide  seasonal  variations  to  which  all  apple 
forms  are  subject,  there  is  hesitation  in  declaring  that  native  crabs 
are  habitually  self-sterile.  It  is  thought  that  self-pollination  of  a 
much  larger  number  of  flowers  carried  on  thru  an  additional  series  of 
years  on  trees  grown  under  other  and,  possibly,  slightly  different  con- 
ditions might  lead  to  results  different  from  those  here  recorded.  In 
any  event,  such  procedure  wyould  supply  a  much  more  stable  basis 
upon  which  conclusions  regarding  the  actual  degree  of  self-sterility 
attaching  to  our  native  crab  forms  could  rest. 

Introduced  Forms. — In  order  to  avoid  giving  the  impression  that 
self-sterility,  as  an  attribute  of  apple  forms,  is  possessed  solely  by  our 
native  species,  reference  should  here  be  made  to  self-pollination  of 
flowers  on  the  much  larger  group  of  introduced  crabs  or  crab-like 
forms  of  apples. 


1988] 


NATIVE  CRABS:   THEIR  BEHAVIOR  I%T  BREEDING 


557 


Flowers  have  been  self -pollinated  on  38  of  the  foreign  crab  forms 
in  the  Station  collection.  These  self-pollinations  aggregate  10,511  and 
were  distributed  thru  the  fifteen  years  1912  to  1926. 

TABLE  7. — SELF-POLLINATION  OF  FLOWERS  OF  NATIVE  CRABS 


Number 
of 

Number 
of 

Number 

of  seeds 

Number 
of 

Species 

Year 

flowers 
selfed 

fruits 
matured 

Planted 

Germi- 
nated 

seedlings 
living 

Malus  coronaria  .  .  . 

1918 

4 

3 

9 

0 

1926 

72 

0 

Mains  ioensis  

1917 

114 

1 

2 

0 

1921 

76 

0 

1925 

50 

0 

1926 

47 

2 

'3 

'6 

Malus  soulardi  .... 

1914 

11 

0 

1916 

4 

0 

1917 

5 

0 

1917 

128 

0 

1918 

6 

0 

1922 

39 

0 

1924 

21 

0 

1926 

50 

0 

Mercer  County 

Crab  

1919 

14 

0 

1920 

30 

0 

1922 

48 

0 

Malus  dawsoniana  . 

1925 

48 

0 

1926 

73 

2 

'4 

i 

'i 

Twelve  forms,  with  1,744  self-pollinations,  matured  no  fruits;  3 
forms,  with  690  self-pollinations,  produced  7  fruits  that  were  seedless; 
2  forms,  with  225  self-pollinations,  matured  5  fruits  containing  4  seeds, 
none  of  which  germinated;  2  forms,  with  601  self-pollinations,  pro- 
duced 7  fruits  containing  2  seeds,  both  of  which  germinated,  but  the 
seedlings,  having  no  vitality,  died  soon  after  appearing  above  ground; 
2  forms,  with  1,487  self-pollinations,  produced  373  fruits  containing 
819  seeds,  29  of  which  germinated,  and  19  seedlings  lived  to  be  trans- 
ferred to  nursery,  but  all  died  before  the  end  of  the  first  year. 

Thus  21  of  the  38  foreign  crab  forms,  representing  45.16  percent 
of  the  total  of  self-pollinations  on  members  of  the  foreign  crab  group, 
failed  and  have  no  seedlings  from  self-pollinations.  The  aggregate  of 
self-pollinations  on  the  21  forms  recorded  as  failing  completely  was 
4,747.  From  these,  392  fruits  matured.  The  fruits  contained  830 
seeds,  only  31  of  which  germinated ;  the  seedlings  were  so  deficient  in 
vitality  that  they  could  not  live  and  all  died  within  a  few  months. 

Each  of  the  remaining  17  forms  of  this  group  of  introduced  crab 
forms  is  represented  by  one  or  more  seedlings  grown  from  fruits  from 


558  BULLETIN  No.  311 

self-pollinations.  Nine  of  the  forms  hold  representation  in  this  group, 
each  thru  a  single  seedling,  and  each  of  the  nine  is  thus  quite  liable 
to  elimination  thru  death  of  its  one  seedling. 

This  group  contained  103  seedlings.  These  seedlings  represent  the 
product  from  the  self-pollination  of  5,764  flowers,  which  matured  548 
fruits  containing  1,533  seeds,  of  which  425  germinated.  That  most  of 
the  seedlings  were  deficient  in  vitality  is  shown  by  the  fact  that  nearly 
76  percent  of  them  have  died  and  that  a  considerable  number  of  those 
still  living  are  graded  as  poor. 

Only  two  of  the  forms  in  the  group  have  shown  what  may  be  re- 
garded as  a  certain  degree  of  self-fertility.  With  each  of  the  two 
forms  this  tendency  to  an  exhibition  of  self-fertility  occurred  in  only 
one  of  several  years,  and  the  year  of  high  production  was  not  the 
same  for  both  forms.  One  of  the  forms  referred  to  is  19651  M.  pruni- 
folia  var.,  which,  while  it  failed  writh  17  self-pollinations  in  1916. 
with  23  in  1918,  with  90  in  1919,  and  from  316  self-pollinations  in  the 
greenhouse  in  1917  produced  one  seedless  fruit,  did,  from  120  self- 
pollinations  on  a  tree  in  orchard  in  1917,  mature  112  fruits,  or  was 
93.33  percent  successful  in  fruit  production.  The  112  fruits  contained 
637  seeds,  of  which  176,  or  27.62  percent,  germinated;  114  seedlings 
were  transferred  to  nursery,  26  of  which  were  living  in  the  fall  of 
1926  at  nine  years  of  age.  Eleven  of  the  seedlings  graded  as  good 
and  are  quite  certain  to  attain  fruit  production;  9  are  graded  as  fair 
and  are  regarded  as  doubtful;  6  are  graded  as  poor  and  are  expected 
to  die  before  fruiting.  The  other  of  the  two  forms  appearing  to  be  in 
a  degree  self-fertile,  in  one  of  the  nine  years  over  which  the  aggregate 
of  405  self-pollinations  are  distributed,  is  19644  M .  microcarpa.  In  six 
of  the  years,  with  a  total  of  189  self-pollinations,  no  fruits  were  ma- 
tured. In  1917  the  self-pollinations  numbered  95,  and  they  matured 
4  fruits  containing  4  seeds,  which  did  not  germinate.  In  1918  there 
were  51  self-pollinations,  which  matured  6  fruits  containing  1  seed; 
this  seed  germinated,  but  the  seedling  died  soon  after  appearing  above 
ground.  In  1925  one  of  32  self-pollinations  matured  a  fruit,  but  it  was 
seedless.  On  a  greenhouse  tree  in  1919,  however,  38  self-pollinations 
matured  21  fruits;  thus  55.26  percent  of  the  self-pollinations  were  suc- 
cessful in  fruit  production.  The  21  fruits  contained  66  seeds,  49,  or 
74.24  percent,  of  which  germinated,  and  44  seedlings  were  transferred 
to  nursery.  Of  these  seedlings  32  were  living  in  the  fall  of  1926  at 
seven  years  of  age;  they  graded  as  7  good,  19  fair,  and  6  poor,  and  as 
with  the  seedlings  from  self-pollinations  on  19651  M.  prunifolia  var., 
those  grading  good  are  expected  to  fruit,  those  grading  fair  must  be 
regarded  as  doubtful,  and  those  grading  poor  are  quite  certain  to  die 
before  reaching  fruit  production. 

The  form  standing  next  below  the  two  forms  mentioned  in  num- 
ber of  living  seedlings  from  self-pollinations  is  19667  M.  mains  var. 


1928}  NATIVE  CRABS:   THEIR  BEHAVIOR  IN  BREEDING  559 

There  are  13  seedlings,  but  instead  of  being  the  product  of  self-pollin- 
ations of  a  single  season,  they  are  from  self-pollinations  made  in  four 
years.  One  seedling  is  eleven  years  old  from  self-pollinations  made  in 
1915;  7  are  nine  years  old  from  self-pollinations  of  1917;  4  are  seven 
years  old  from  self-pollinations  made  in  1919;  and  1  is  two  years  old 
from  self-pollinations  of  1924.  At  the  time  of  taking  the  growth 
record  in  the  fall  of  1926  not  one  of  the  seedlings  was  rated  as  good; 
the  eleven-year-old  tree  was  poor;  of  the  7  completing  their  ninth 
year  6  rated  poor  and  1  fair;  the  4  at  seven  years  of  age  rated  as  2 
poor  and  2  fair,  and  the  tree  two  years  old  was  poor.  Thus  for  the 
group  10  graded  as  poor  and  3  as  fair;  none  of  the  seedlings  were 
vigorous.  While  the  percentage  of  fruit  production  was  50.54,  the 
seed  content  of  2.44  to  each  fruit  was  low,  germination  was  only  21.40 
percent,  and  the  seedlings  were  of  low  vitality,  as  is  shown  by  the  fact 
that  almost  90  percent  have  died  and  77  percent  of  those  living  are 
graded  as  poor  and  these  will  certainly  die  before  attaining  fruit  pro- 
duction. 

This  group  would  appear  not  to  be  entitled  to  credit  for  any 
degree  of  self-fertility,  and  the  elimination  of  the  group  before  any  of 
the  seedlings  reach  fruit  production  is  anticipated.  There  are  five 
others  in  this  group  of  foreign  crabs  that  have  no  seedlings  graded  as 
good,  and  the  six  forms  may  properly  be  added  to  the  21  forms  that 
are  not  represented  by  seedlings,  making  27  forms  that  have  failed  in 
this  test  of  self- fertility  and  should  be  classed  as  self-sterile.  Only  11 
forms  have  seedlings  that  grade  as  good  and  7  of  these  are  represented 
by  a  single  individual  each. 

From  the  record  of  self-pollinations  on  foreign  crab  forms  it  ap- 
pears that  forms  included  within  the  groups  are,  as  a  rule,  self-sterile. 
Exceptions  occur,  but  in  no  form  do  they  occur  with  sufficient  regu- 
larity to  make  the  form  useful  in  breeding  operations. 

Comparing  the  two  groups  of  crab  forms,  the  native  with  the 
foreign,  there  is  little,  if  any  difference  between  them.  Members  of 
both  groups  are,  in  the  main,  self-sterile. 

A  third  group  of  apple  forms,  which  includes  the  named  varieties 
commonly  planted  in  orchards,  may  be  included  as  part  of  the  survey 
of  self-pollinations. 

On  35  orchard  varieties  3,485  flowers  have  been  self-pollinated. 
Twenty  varieties  produced  no  fruit;  4  varieties  produced  1  seedless 
apple  each;  1  variety  produced  one  fruit  which  had  one  seed,  and  the 
seed  failed  to  germinate;  in  another  case  the  one  seed  produced 
germinated  but  the  seedling  died.  Thus  26  varieties  have  no  living 
seedlings  from  self-pollinations. 

Nine  varieties  are  represented  by  living  seedlings,  but  as  a  matter 
of  fact  only  two  varieties  have  seedlings  in  sufficient  numbers  and  of 
such  quality  as  to  suggest  possession  of  any  appreciable  degree  of 


560  BULLETIN  No.  311 

self-fertility.  These  two  varieties  are  Longfield,  a  Russian  variety, 
and  Wythe,  which  originated  as  a  seedling  in  this  state. 

Orchard  Varieties. — Considering  orchard  varieties  as  a  group,  the 
results  obtained  from  self-pollinations  are  much  the  same  as  results 
obtained  with  the  two  crab  groups,  and  thus  one  general  statement  to 
the  effect  that  apple  forms  are  self-sterile  is  warranted.  In  the  eighteen 
years  beginning  with  1909  and  ending  with  1926,  a  total  of  14,836 
flowers  have  been  self-pollinated  on  78  different  apple  forms.  At  the 
end  of  1926  there  were  27  forms  represented  by  living  seedlings.  Fifty- 
one  forms  are  therefore  recorded  as  failing  entirely.  The  living  seed- 
lings produced  by  27  apple  forms  from  self-pollinations  number  252, 
but  only  about  one  of  five  is  graded  as  good  and  experience  has  taught 
that  seedlings  that,  because  deficient  in  vigor,  grade  as  poor  or  fair 
are  not  likely  to  attain  fruit  production  altho  they  sometimes  linger 
for  several  years. 

The  51  seedlings  now  graded  as  good  include  some  that  are  still 
very  young  and  for  this  reason  some  decrease  in  numbers  in  this  group 
may  be  anticipated. 

Conclusions. — Rarely  do  seedlings  grown  from  seeds  developed  in 
fruits  from  self-pollinations  possess  normal  vigor;  most  of  them  are 
endowed  with  so  little  vigor  that  they  cannot  live,  and  they  die  more 
or  less  promptly.  The  few  that  persist  and  promise  attainment  of 
fruit  production  serve  to  emphasize  and  make  clear  the  uncertainties 
and  difficulties  that  must  attend  any  effort  to  produce  a  generation  of 
seedlings  from  a  sufficient  number  of  self-pollinations  to  make  it  pos- 
sible to  determine  accurately  the  principles  involved  in  the  production 
of  seedlings  by  this  method  in  apple  forms. 


UNIVERSITY  OF  ILLINOIS-URBAN* 


